nat: Introduce a block on the NAT to slowly get rid of BSCs
For restarting the NAT we can now block it, it will not accept
new connections and for existing connections it will attempt
to drop them over time. A blocked NAT will end up with no BSC
connections left and then can be safely restarted.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat.c b/openbsc/src/osmo-bsc_nat/bsc_nat.c
index 2950745..bbb2ae3 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat.c
@@ -847,6 +847,23 @@
talloc_free(connection);
}
+static void bsc_maybe_close(struct bsc_connection *bsc)
+{
+ struct sccp_connections *sccp;
+ if (!bsc->nat->blocked)
+ return;
+
+ /* are there any connections left */
+ llist_for_each_entry(sccp, &bsc->nat->sccp_connections, list_entry)
+ if (sccp->bsc == bsc)
+ return;
+
+ /* nothing left, close the BSC */
+ LOGP(DNAT, LOGL_NOTICE, "Cleaning up BSC %d in blocking mode.\n",
+ bsc->cfg ? bsc->cfg->nr : -1);
+ bsc_close_connection(bsc);
+}
+
static void ipaccess_close_bsc(void *data)
{
struct sockaddr_in sock;
@@ -1008,6 +1025,7 @@
con_filter = con->con_local;
}
remove_sccp_src_ref(bsc, msg, parsed);
+ bsc_maybe_close(bsc);
break;
case SCCP_MSG_TYPE_UDT:
/* simply forward everything */
@@ -1168,6 +1186,12 @@
return 0;
}
+ if (nat->blocked) {
+ LOGP(DNAT, LOGL_NOTICE, "Disconnecting BSC due NAT being blocked.\n");
+ close(fd);
+ return 0;
+ }
+
on = 1;
rc = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
if (rc != 0)
@@ -1302,6 +1326,8 @@
static void sccp_close_unconfirmed(void *_data)
{
+ int destroyed = 0;
+ struct bsc_connection *bsc, *bsc_tmp;
struct sccp_connections *conn, *tmp1;
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
@@ -1318,8 +1344,17 @@
sccp_src_ref_to_int(&conn->real_ref),
sccp_src_ref_to_int(&conn->patched_ref));
sccp_connection_destroy(conn);
+ destroyed = 1;
}
+ if (!destroyed)
+ goto out;
+
+ /* now close out any BSC */
+ llist_for_each_entry_safe(bsc, bsc_tmp, &nat->bsc_connections, list_entry)
+ bsc_maybe_close(bsc);
+
+out:
bsc_schedule_timer(&sccp_close, SCCP_CLOSE_TIME, 0);
}